Browsing by Author "Alemu, Sewnet"

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    Influence of Gear Materials on Surface Fatigue Failure of Spur Gear
    (Addis Ababa University, 2013-02) Alemu, Sewnet; Tilahun, Daniel (PhD))
    The objective of this study is to investigate the effect of material on surface durability of spur gear. Current Analytical methods of calculating gear contact stresses use the contact stresses of spur gear. It’s necessary to develop and to determine appropriate models of contact elements, and to calculate contact stresses using ANSYS and compare the results with Hertzian theory. In addition parametric study to investigate the effect of material types in contact stress in gears was performed and Results from ANSYS Workbench, for a 3D model of involute spur gear, shows that contact stress results correlated with theoretical formulation, with tolerable accuracy. It is also shown that the development of finite element analysis model of the Spur gear assembly to simulate the contact stress between two gears reasonable ,and obtained result is compared with the Hertzian theoretical equation. Results of finite element approach for contact stress estimation in ANSYS and Hertz theory, for the material Grey cast iron GG-30,, Grey cast iron-20,and Chromium-molybdenum alloy steel (SCM 420) is compared. The result of the analysis summarized as follow. The maximum contact stress value for these material was, 1088Mpa, 977MPa and 1492Mpa respectively, which obtained by Hertz theory, the well known theoretical calculations method for contact problem. The stress analysis has been done by ANSYS software, where the results have been presented by contours and numerical values. The maximum contact pressure result from ANSYS for 3D model is 1032Mpa, 825MPa, 1414Mpa respectively. Based on the result from the contact stress analysis the hardness of the gear tooth can be improved to resist pitting failure.